Processes that comprise treating crude oil and other petroleum feedstocks with hydrogen in the presence of a catalyst are well known. One such process is hydrocracking, in which heavy distillate hydrocarbons are converted under hydrogen pressure into products of lower molecular weight in the presence of a catalyst. Hydrocracking is used in the oil industry to prepare a wide range of materials, ranging from C3/C4 production to luboil manufacture.
Hydrocracking may be operated as either a single or two-stage process. Two-stage hydrocracking involves a first stage, which is predominantly a hydrotreatment stage wherein impurities and unsaturated compounds are hydrogenated in the presence of a first catalyst having a high hydrogenation function, and a second-stage where most of the cracking occurs in the presence of a second catalyst having a strong cracking function. In single-stage hydrocracking, the treatment and cracking steps occur in one reactor and may be performed using a single catalyst. The catalysts employed in hydrocracking are generally made from a carrier material on which there are deposited catalytically active metals such as nickel, molybdenum, tungsten and palladium.
It is advantageous to have a catalyst which enables the refinery to produce the most attractive product slade for the refinery in question. A product slade which can be advantageous is one having an increased gas oil yield. Gas oils are hydrocarbons boiling in the range of from 250 to 370° C. at atmospheric pressure, and are suitable for use as diesel. Especially in Europe and Asia, there tends to be an increased demand for diesel and reduced demand for gasoline. Further, an improved denitrogenation was observed.